Fatal error on Ultimate Facebook plugin activation

Hello WPMU Dev. I got the next warging...

"Fatal error: Uncaught exception 'Exception' with message 'Facebook needs the CURL PHP extension.' in /var/www/wp-content/plugins/wpmu-dev-facebook/lib/external/base_facebook.php:19 Stack trace:
#0 /var/www/wp-content/plugins/wpmu-dev-facebook/lib/external/facebook.php(18): require_once()
#1 /var/www/wp-content/plugins/wpmu-dev-facebook/wpmu-dev-facebook.php(102): require_once('/var/www/wp-con...')
#2 /var/www/wp-admin/plugins.php(146): include('/var/www/wp-con...')
#3 /var/www/wp-admin/plugins.php(148): plugin_sandbox_scrape('wpmu-dev-facebo...')
#4 /var/www/wp-admin/network/plugins.php(16): require('/var/www/wp-adm...')
#5 {main} thrown in /var/www/wp-content/plugins/wpmu-dev-facebook/lib/external/base_facebook.php on line 19 "

... when I activated the Ultimate Facebook plugin in my network. How can I solve this problem. Thanks in advance.

ANIMSA